GM Diesel Exhaust Fluid Buyer's Guide

Every modern diesel vehicle uses diesel exhaust fluid (DEF). If you own a diesel vehicle, it’s important to know what DEF is and how to replace it. This buyer’s guide has all the information you need on DEF.

What Is Diesel Exhaust Fluid And Why Is It Important?

DEF pump

Diesel exhaust fluid is an important part of your vehicle’s emissions system. DEF is a non-hazardous fluid that breaks down harmful nitrogen oxide emissions into a mixture of nitrogen and water. DEF is injected into the emissions system to break down the nitrogen oxide before it’s released into the air. Read this post for a more thorough explanation of what DEF is and how it works.

What Does The 'Diesel Exhaust Fluid Low' (DEF) Indicator Mean?

If you have a diesel vehicle, your dashboard has a DEF indicator. It may be a light in the dash or a message on the LED screen. The indicator exists to inform you of the status of the DEF in your vehicle’s Selective Catalytic Reduction (SCR) system. The most common issues include:

  • Low levels of DEF
  • A pressure problem within the SCR system
  • Contamination in the DEF tank

It’s important to pay attention to the DEF indicator once it notifies you of a problem. If you don’t address the issue right away, serious problems may arise. If you want to read more about DEF indicators and why they’re important, check out this post.

How To Replace A Diesel Exhaust Fluid Pump

Has your DEF pump failed? This tutorial will walk you through the replacement process. On most GM diesel vehicles, the DEF pump is mounted on top of the DEF tank. In some vehicles, you’ll find the pump inside the tank. All you need to do is drop the tank and then remove the pump. The tutorial also includes some important tips to ensure that the replacement goes smoothly.

How To Replace Diesel Exhaust Fluid 

Adding diesel exhaust fluid

If you need to add more DEF, this tutorial will help you. To sum it up, you would only need to do this to replace the DEF: with a funnel in the filler, pour the DEF into the tank. The important thing is to add DEF as soon as the low DEF warning light goes on. If you don't, the vehicle may go into limp mode as the DEF gets really low.  

How To Replace A Diesel Particulate Filter

Replacing the DPF is a more labor-intensive process. You would need to:

  1. Jack up the front of your vehicle
  2. Find the DPF and then remove it
  3. Install the new DPF

Do you have any questions about DEF fluid or diesel particulate filters? Please get in touch with us. We'll be happy to help!